Analysis Events Leading to Collision The multi-coloured lights displayed by Mistral impaired the ability of the Tiger Shaman's crew to recognize the distinctive character of the Mistral's navigation lights and made it impossible to determine the aspect of the brightly lit pleasure craft. The Mistral was not equipped with radar; the owner maintained a visual lookout as he operated the vessel. However, 10 people were in the wheelhouse, where conversation and music provided distractions as the two vessels approached each other. The use of the tug's spotlight alerted the operator of the Mistral to the former's presence. However, the Mistral's operator experienced difficulty in ascertaining its relative bearing due to the reflections created by the wheelhouse windows. This, in combination with the back scatter from its Christmas lights, would have hindered the Mistral's ability to maintain a proper look-out2. The distractions, impaired visibility, and the effects of alcohol may account for: the operator's delay in detecting the Tiger Shaman until it was at an estimated range of 160 m; and the Mistral's alteration of course to port into the path of the tow. Prior to the operator of the Mistral observing the Tiger Shaman, the tug made an alteration to port and reversed its engines to avoid a collision. As the barge was at the end of the tug's 90 m tow wire, it would have continued on its original heading and remained closer to the centre of the navigable channel. The tug's alteration, therefore, would have had minimal impact on the original track of the Packmore4000. As it was a dark night with few shore lights in the vicinity, the lights of the tug which were higher above the water than those of the barge would have been more readily visible. The Mistral's master, unaware of the tug's collision-avoidance actions and without the benefit of radar, may have been expecting to see the tow lights to his starboard, whereas they were on his port side. It is, therefore, likely that the operator of the Mistral did not see the barge's green light. Although the operator of Mistral recognized that the tug was displaying towing lights, i.e., two masthead lights one above the other, he did not see the barge under tow. However, the COLREGS are clear with regard to the determination of risk of collision and require that if there is any doubt, such risk shall be deemed to exist.3 These rules also require that, in order to avoid a collision or allow more time to assess the situation, a vessel shall slacken her speed or take all way off by stopping or reversing her means of propulsion.4 The Mistral did not take any of these measures. Performance of the Packmore4000's LED Barge Lamp The starboard LED light was removed from the barge and sent to the TSB Engineering Branch Laboratory to be performance-tested together with another LED light of the same model used aboard the Packmore4000 and supplied by Transport Canada. The TSB laboratory made calculations to determine minimum required luminous intensities at intermediate ranges that would equate to the requisite 12 candelas at 3 miles. Using the formula, the maximum observed output was 16.45 candelas 37 per cent beyond the 3-mile range requirement. However, the vertical sector of the emitted light from the lamp exceeding 12 candelas was approximately 1.8 degrees, and the vertical sector exceeding 7.2 candelas was 4.9 degrees. On the night of the occurrence, the LED sidelights on the Packmore4000 were fitted into the appropriate brackets welded to the leading face of the bulwarks, port and starboard. The bulwarks are erected perpendicular to the deck of the barge, and the brackets are aligned so that the zero axis of the light shines parallel to the water plane when the barge is trimmed to an even keel. The empty barge was trimmed 10 cm by the stern, which would change the horizontal plane by less than 0.1. This change would not significantly affect the performance of the lamp. The Packmore4000's starboard sidelight was observed by the Tiger Shaman's crew members to be operating before the collision and again, by the master of the Siyay, after the collision. TSB laboratory tests found that the light was available to be seen from the relative positions of the observer. From the TSB Engineering Laboratory tests, it was concluded that: The portable navigation lamp in use at the time of the occurrence was certified for use on unmanned barges. Properly configured, these lamps meet the horizontal luminous intensity requirements as set forth in the Marine Navigation Lights standard UL 1104 . These portable, battery-powered lamps do not meet the vertical luminous criterion for other commercial vessels stipulated in the UL 1104 standard, nor are they required to meet the vertical specification when used on unmanned barges in Canadian and United States waters. A potential exists to misalign the head and base assemblies of these lamps. This may result in a lamp's failure to meet the horizontal luminous intensity requirement. The manufacturer does not provide alignment documentation. It was not possible to determine the lamp's configuration (i.e., lens cap, LED array holder, and base assembly alignment) at the time of the occurrence. A properly configured lamp would have been visible to the approaching pleasure craft. Note: This assumes no line-of-sight obstructions. TSB Engineering Report LP 008/04 entitled Marine Collision Light Analysis - MISTRAL PACKMORE 4000 is available upon request. Three factors determine the distance at which a lamp can be sighted: the vertical sector component of the lamp, its height above sea level, and the height of the observer's eye on an approaching vessel. Even if an approaching vessel is within a lamp's (theoretical) horizontal visible range, however, the narrow vertical sector component can preclude navigators on that vessel from actually seeing the light. Thus, the exemption of unmanned barges from the vertical sector component requirements applicable to other commercial vessels can impede visual detection of light, and make any misalignment(for whatever reason), safety-critical. The multi-coloured Christmas lights exhibited by the Mistral impaired both the visibility and the distinctive character of that vessel's navigation lights such that the vessel's aspect could not be determined. The multi-coloured lights and the presence of nine additional non-watchkeeping personnel in the wheelhouse interfered with the operator's ability to keep a proper lookout. The operator of the Mistral had consumed alcoholic beverages, and his blood-alcohol level was in excess of the legal limit. The collision-avoidance actions taken by the Tiger Shaman were not recognized by the operator of the Mistral. This action changed the aspect of the tug relative to the barge and may account for the Mistral not seeing the barge at its anticipated location. Although the approaching vessel was identified by the Mistral as a towing vessel and the location of the tow was not determined, the pleasure craft neither stopped nor slowed to allow more time to assess the situation.Findings as to Causes and Contributing Factors The multi-coloured Christmas lights exhibited by the Mistral impaired both the visibility and the distinctive character of that vessel's navigation lights such that the vessel's aspect could not be determined. The multi-coloured lights and the presence of nine additional non-watchkeeping personnel in the wheelhouse interfered with the operator's ability to keep a proper lookout. The operator of the Mistral had consumed alcoholic beverages, and his blood-alcohol level was in excess of the legal limit. The collision-avoidance actions taken by the Tiger Shaman were not recognized by the operator of the Mistral. This action changed the aspect of the tug relative to the barge and may account for the Mistral not seeing the barge at its anticipated location. Although the approaching vessel was identified by the Mistral as a towing vessel and the location of the tow was not determined, the pleasure craft neither stopped nor slowed to allow more time to assess the situation. The misalignment of a Light Emitting Diode (LED) barge navigation lamp could significantly reduce its visible range, due to the narrow vertical sector of emitted light, and as the manufacturer does not provide alignment documentation. The exemption of unmanned barges lamps from the vertical sector component requirements applicable to other commercial vessels makes any misalignment safety-critical and may deprive navigators on the approaching vessel from sighting the light in sufficient time to take collision-avoidance action.Findings as to Risk The misalignment of a Light Emitting Diode (LED) barge navigation lamp could significantly reduce its visible range, due to the narrow vertical sector of emitted light, and as the manufacturer does not provide alignment documentation. The exemption of unmanned barges lamps from the vertical sector component requirements applicable to other commercial vessels makes any misalignment safety-critical and may deprive navigators on the approaching vessel from sighting the light in sufficient time to take collision-avoidance action. It was not possible to determine the lamp's configuration at the time of the occurrence.Other Finding It was not possible to determine the lamp's configuration at the time of the occurrence. Safety Action Action Taken Following the occurrence, the TSB met with the Council of Marine Carriers (CMC) and expressed concerns about the Light Emitting Diode (LED) navigation lamps. Safety Concern Performance Requirements for LED Navigation Lamps on Unmanned Barges The Collision Regulations have established that the minimum range of visibility for navigation sidelights must be three miles, thereby allowing vessels sufficient time to evaluate the risk of collision and take collision-avoidance action. Although the use of LED lamps for barges in recent years has increased the visibility range of the lights, their narrow vertical-sector component can limit the actual horizontal range at which light may be sighted. The LED lamps tested showed that, at the minimum three-mile range requirement, the vertical luminous sector was approximately 1.8 degrees, in contrast to the 5 degree vertical luminous sector requirement for other commercial vessels. Consequently, any characteristic that obstructs line-of-sight detection or substantive misalignment of an LED barge navigation lamp would reduce its visible range due to the narrow vertical sector of emitted light, even if it exceeds the minimum intensity requirements. There are over 2000 barges registered in Canada, of which a large number are without their own power source and therefore rely on the battery-powered LED lamps. The Board, therefore, is concerned that the unmanned barges will continue to carry navigation sidelights that may not be visible at the minium range for all conditions of operation, thereby increasing the chance of accidents and subjecting other vessels to undue risk. The Board will continue to monitor the situation.